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Transmitter site re-hab

One of the reasons for the recent lack of posts; I have been busy rehabilitating several transmitter sites for various broadcasting companies. These are mostly FM transmitter sites and vary in power from one kilowatt to twenty six kilowatts ERP.  I enjoy project work, but I have been driving hither and yon, racking up 27,000 miles on my new car since last August.

Subaru Crosstrek XV at remote transmitter site, somewhere in rural New York

Subaru Crosstrek XV at remote transmitter site, somewhere in rural New York

So, here is one transmitter site that I just finished; WFLY, Albany, New York.  Removed Collins 831F2 transmitter which was functioning as a backup and installed new Broadcast Electronics FM20S.  The Continental 816R2 is becoming a little bit long in the tooth for a main transmitter, being new in 1986.  Thus, it was time to install a new unit, and I like the Broadcast Electronics solid state and tube designs.  With the BE AM and FM solid state units, their simplicity is their beauty.  We service many BE transmitters, some are thirty years old and are still supported by the manufacturer.

WFLY transmitter building, New Scotland, NY

WFLY transmitter building, New Scotland, NY

The BE FM20S transmitter is actually two FM10S cabinets combined with one controller.  Each cabinet requires a 100 amp three phase mains connection.  This station’s TPO is 11.5 KW, so there is plenty of head room in case the owner’s ever want to install HD Radio or replace the three bay antenna with a two bay unit.

WFLY main transmitter, Broadcast Electronics FM20S

WFLY main transmitter, Broadcast Electronics FM20S

In transmitter cabinet two, above the exciter is room for HD equipment.

BE FM20S exciter housing

BE FM20S exciter housing

I also reworked the coax switches to provide easier implementation of the backup transmitter.  Basically, the main transmitter is on the main antenna, the backup transmitter is on the backup antenna.  We can move the second coax switch to test the backup into the dummy load.  We can move the first coax switch to change antenna feeds.

WFLY backup and main transmitters

WFLY backup and main transmitters

Pretty standard setup.

WFLY RF path diagram

WFLY RF path diagram

We moved the Collins 831F2 from Albany to here to replace another, dead Collins unit at WKXZ in Norwich, New York.  This transmitter is forty years old, but still runs reliably.  Of course, doing this work in the dead of winter added a degree of difficulty to the job, as the roads to both the WFLY and the WKXZ transmitter sites needed work to make them passable for a moving truck.  In the end, we used a skid steer with forks on it to get the transmitter up the final hill and into the small WKXZ transmitter building.

Collins 831F2 transmitter, WKXZ, Norwich NY

Collins 831F2 transmitter, WKXZ, Norwich NY

Collins 831F2 transmitter

Collins 831F2 transmitter

The WKXZ transmitter building interior is floor space challenged. It is located next to a former TELCO microwave site which has a guyed tower.

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10 comments to Transmitter site re-hab

  • Jim Seaman

    Nice to see an old workhorse escape the scrap heap. Although very reliable, I always thought the Continentals were death traps with the driver tuning control deep inside the rig, not far above the HV filter capacitor. At least that’s how I recall them! I’m badly out of touch with BE’s product line, but presume the FM20S has SSPA’s for a final. I got started when tube transmitters was all there was. Everybody likes to see new gear, but it’s bittersweet to sit back and watch as tube-type transmitters slowly fade into oblivion. We all remember the mantra, “peak the grid, dip the plate”, and have had to warn the new guys about tuning for “maximum smoke”. Solid-state just has no romance about it, and I prefer to see my radios glow in the dark.

  • Rene Tetro

    It was nice to see the old Collins rig at WFLY. Jim Cruise and I installed that (with a lot of help from Ken Branton of Collins/Rockwell). We installed an ERI rototiller at the same time and relegated an old GE transmitter as backup (I believe it was a 5KW rig). I used to spend a lot of time at the site. I remember that the second floor had living quarters from the days when the site was manned. I actually napped up there in one of the beds several times after pulling all nighters. This was all back around 1976-80.

  • Chris R

    I love that simple stuff. No touch screens or such nonsense you won’t be able to replace in five years. Jim, I remember the 817 and that tuning control. Scarey!

  • Jim Seaman

    The WFLY GE rig was a full 250W transmitter connected to a 3kW amplifier cabinet. The original Phasitron exciter had been replaced by a feed from the Collins exciter. By the time I engineered WFLY, the cot in the engineer’s living quarters was still there, but the mattress and most of the building was “staffed” full-time by rodents. After all those years of manned and unmanned operation, we used to joke, “if only that mattress could talk!”

  • Paul Thurst

    That Collins rig is still a pretty solid unit. We had to replace one SCR on the plate supply, and re-tap the transformers for different AC voltage, other than that, it is in remarkably good shape. The living quarters are still there, but the cot/mattress are long gone. I can imagine when the site was manned, it was probably pretty nice up there in the summer time, in the winter time, not so much.

  • When I got the tour of WFLY , almost 20 years ago, I actually got to see the Collins on the air. While I was there, the engineer at the time switched back to the Continental after repairing the exciter(?). I forgot exactly what had happened, other than the site had taken a nasty lightning hit, which knocked out a couple of bullets in the ERI.

    The LPTV that was there moved over to 17’s old tower , correct?

  • Dave Porter G4OYX

    Hi Chaps,

    On the same theme of saving TX equipment please take a look at this thread from a UK site re saving a BBC 40kW analogue tv tx from crystal Palace London.

    http://electrokinetica.org/forum/viewtopic.php?f=3&t=411

    73

    Dave

  • Nick Straka

    Trusty Subaru! My 2008 Outback has racked up 263,000 miles on it, traveling to all the transmitter and studio sites. Yours has the 4 in it, change the timing belt every 100k and check the head gasket around 150k for any leaks. Feed with tires and brakes, and she will rust out before she stops running.

  • Steve Brown

    Nice planning on the two Dielectric switches for RF transfer, Paul. I would add that when planning the control for the switching routine it’s a good idea to first operate the switch manually with an ohmmeter connected to the various auxiliary microswitch contacts to see not only when they open and close, but how fast. The way the auxiliary switches are mounted, one of them that goes open when the switch moves happens BEFORE the other one does the same thing. Use the FIRST switch to control the transmitter interlocks, and the second for status or anything else. I use a macro in the remote control to first turn off both transmitters and verify that with status feedback before issuing a switch command, but just in case someone decides to move the switch manually with RF applied there’s a better chance of not burning up the RF switch contacts.

  • Paul Thurst

    Nick, I like the Subaru, it was a good purchase and is turning out to be a solid car. I sometimes miss having a pickup truck, but do not miss filling the 30 gallon associated.

    Steve, good idea. We have the custom length cables coming from dielectric. When I install them, I will check the switch sequence as you suggested. I’ve seen these switches burn up before, and it is not pretty. My idea was to have the switches configured so that neither needs to be moved by the DJ to get the backup transmitter on the air. The only time the switches should move is when we are on site, testing a transmitter into the dummy load.

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